1. Field of the Invention
The present invention relates to systems and processes of wastewater treatment and, in particular, to systems and methods of treating wastewater utilizing sequencing batch reactors with membrane filtration systems.
2. Description of the Related Art
Pilgram et al., in U.S. Pat. No. 6,383,389, which is incorporated herein by reference, teach a wastewater treatment system and method of controlling the treatment system. A control system can sequence and supervise treatment steps in a batch flow mode of operation or a continuous flow mode of operation.
Daigger et al., in U.S. Pat. No. 6,517,723, teach a method and apparatus for treating wastewater using membrane filters. The apparatus includes a bioreactor for containing a mixture of wastewater under treatment and activated sludge. The bioreactor is divided into a plurality of serially connected treatment zones. A membrane filter is downstream of an aerobic zone of the bioreactor.
Mikkelson et al., in U.S. Pat. Nos. 6,613,222 and 6,875,357, teach a process and apparatus for the treatment of wastewater. A three-phase cycle, including a mix fill phase, a react fill phase, and react discharge phase, is used. The need for separate basins for anaerobic and anoxic conditions, and a quiescent environment for solids/liquid separation as in conventional sequencing batch reactor systems is eliminated.
Johnson et al., in U.S. Pat. No. 7,014,763, teach multiple barrier biological treatment systems. In a sequencing batch reactor system, the activated sludge, biochemical reaction stages are separated from and independent of the clarification and sedimentation stages.
Dimitriou et al., in U.S. Pat. Nos. 7,118,674 and 7,179,370, disclose an energy-efficient biological treatment with membrane filtration apparatus and process. The biological treatment section is physically separated from the filtration section.
DiMassimo et al., in U.S. Pat. No. 7,147,778, disclose a method and system for nitrifying and denitrifying wastewater. The system has reactors that nitrify or denitrify wastewater and a membrane reactor that operates under aerobic conditions.
Reid, in U.S. Pat. No. 7,156,998, teaches a phased activated sludge system that incorporates batch treatment techniques in a flow-through process. The mixing and aeration systems are independent to facilitate the operation of the main reactor vessel in aerated and anoxic conditions.